ABSTRACT
Asphaltene deposition is a major problem both upstream and downstream in the petroleum industry.1-5,184 Asphaltenes are known as the “cholesterol” of crude oil. Asphaltenes can block reservoir pores in the near-well area and deposit in the production tubing and downstream pipeline and facilities.6 Many reservoirs with crudes containing asphaltenes produce without evidence of asphaltene deposition until the oil stability is disturbed or destabilized. Asphaltenes are destabilized by gas breakout (pressure drop), condensate treatments, gas or gas liquid injection (CO2, NGL oods), acid stimulation (see Chapter 5), low-pH scale inhibitor squeeze treatments, crude blending,185 and high shear or streaming potential. If this destabilization occurs in a formation that contains charged minerals, the asphaltenes can adsorb and alter wettability and permeability.7 A high concentration of asphaltenes in a crude does not necessarily result in an asphaltene deposition problem. In fact, crudes with as much as 20% asphaltenes may present no deposition problems, whereas crudes with asphaltene contents as low as 0.2 wt.% have been shown to cause asphaltene deposits.8
